Assisted-listening systems and/or devices, e.g., hearing aids, may utilize an electret microphone for converting sound energy to an electrical signal, signal processing circuitry for processing the electrical signal, and a receiver for converting the electrical signal to acoustical energy. Typically, the signal processing circuitry includes input buffer circuitry having an input impedance to match the output impedance of the electret microphone. The input buffer circuitry often includes a MOS transistor that is subject to undesirable 1/f noise, also called excess noise, or flicker noise.
The present invention is directed to solve these and other problems.